As an electrical Engineer, can you take the thing apart and tell us what relay this is and why it is switching? (cannot find the service manual, either)
What happens to the power drawn by the Receiver?
I have experienced/heard the switching after several dozen or so minutes of just playing background music.. sounds to me like the amp just switching off certain things, cranking down the internal stuff because it's not needed.
But what you describe appears to be something different entirely. As if the amp tried to protect itself.
Did you drive output past 0dB setting (Volume control), too?
How did you measure the signal with 8 Ohms loads? (I'm no electrical engineer, just trying to understand the implications of this for real people)
Now, 25 Watts for me is 96dB from a single speaker.. that's basically the peak SPL I would expect when playing a movie on the -10dB setting (105dB is reference level)
never for 30 seconds straight, though..
But I really want to understand how these things come to be, because the amplifier has more than enough power from the psu (700+ Watts) and it was rated at 100+ Watts per channel and actually measured by acclaimed audio magazines to put out the rated amount of power into 5/7 channels respectively.
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